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could you help me with these tow problems...... 8x/x+1 - 3/x+1 and this one 6/7x + 1/4

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2 Answers

You need to find the lowest common denominator for both problems so you can combine the factors. For the first problem, since the denominators are the same, then you can just add the two numerators together, thus you end with (8x-3)/(x=1). For the second equation, you need to calculate the LCD. The easiest way to determine a common denominator is to multiply all of the denominators involved (in this case 4 and 7x)and then reduce if possible. Then you can combine the numerators and then reduce the answer if possible.

Hope this helps

With any addition/subtraction of two fractions, your first step is finding a Common Denominator. The denominator is the bottom number of the fraction. Do this by finding a "multiple" of the two denominators. An easy way to find one is to simply multiply the two denominators together.

However, you're first problem is a subtraction of two fractions written with their Lowest Common Denominator (LCD), which is (x + 1)

8x / (x + 1) - 3 / (x + 1)

Since both fractions are already written with their LCD, second step we subtract the numerator of the second fraction from the numerator of the first fraction. The numerator is the top number of the fraction:

8x - 3

Third step, take the common denominator that you figured out in Step 1 and add it on the bottom of your new numerator.

(8x - 3) / (x + 1)

Last step, simplify and reduce. Simplify by dividing both the numerator and the denominator in the fraction by each number's greatest common factor. However, this first problem is already simplified.

 

With the second problem, it's an addition of two fractions with unlike denominators:

6/7x + 1/4

First step, find a common denominator. Again, you do this by finding a "multiple" of the two denominators. An easy way to find one is to simply multiply the two denominators together:

7x * 4 = 28x

Second step, multiply both numbers on the first fraction by the bottom number of the second fraction. We're not changing the value of the fraction; we're just changing how the fraction looks. It's still the same fraction:

6/7x * 4/4 = 24/28x

Third step, Multiply both numbers on the second fraction by the bottom number of the first fraction. Again, we're not changing the value of the fraction; we're just changing how the fraction looks. It's still the same fraction:

1/4 * 7x/7x = 7x/28x

Line both fractions up side by side with their new numbers. We haven't added them yet, but that will come soon! What we've done is multiple each fraction by the number 1. Fourth step, add together the numerators of the two fractions. The numerator is the top number of the fraction.

24 + 7x

Fifth step, take the common denominator that you figured out in Step 1 and add it on the bottom of your new numerator.

(24 + 7x) / 28x

Last step, simplify and reduce. Simplify by dividing both the numerator and the denominator in the fraction by each number's greatest common factor. However, this second problem is already simplified.